This application claims the benefit of German patent application 103 39 875.9 filed Aug. 29, 2003, herein incorporated by reference.
The invention relates to a channel plate for an open-end rotor spinning device.
Open-end spinning devices with a rotor housing open toward the front, which is closed off by means of a so-called channel plate during spinning, are part of the prior art and have been extensively described in numerous protection rights applications.
Channel plates are known in this connection, which are directly integrated into a pivotably seated cover element of the open-end spinning device, as well as channel plates which can be screwed into the cover element. Moreover, channel plates are known which have a central bearing receptacle, in which a channel plate adapter can be easily interchangeably fixed in place.
For example, modern open-end spinning devices have a fiber channel plate integrated into the cover element which, by means of a lip seal, closes off the rotor housing which is charged with an underpressure during the spinning process.
In this case a draw-in roller and an opening roller for the sliver are additionally seated in the cover element, which covers the entire front of the open-end spinning device.
Such a channel plate with an interchangeable channel plate adapter is described relatively extensively in German Patent Publication DE 197 29 192 A1, for example.
The channel plate body substantially consists of an insert body, whose contact face is exactly matched to the shape and the size of the central bearing receiver in the fiber channel plate, as well as of a channel plate tower extending into the spinning rotor when the spinning device is closed. An arresting shoulder with a central bore, in which a small yarn draw-off tube is positioned, is arranged at the rear of the insert body.
Such a channel plate adapter can be fixed in place in a definite manner in the bearing receiver of the fiber channel plate by means of the arresting shoulder, as well as an appropriate locking element, for example a bar spring. The central bore in the insert body also penetrates through the channel plate tower, at whose front face a yarn draw-off nozzle has been fixed in place, which engages the central bore of the channel plate adapter.
Moreover, the channel plate tower has on its shell face the outlet opening of a fiber guide channel, which connects the sliver opening device arranged in the cover element with the spinning rotor in a continuously pneumatically connected manner.
Preferably such channel plate adapters are matched to a definite rotor shape and/or rotor size, so that it is possible under all production conditions to assure a correct sliver feed-in and optimal yarn draw-off. This means that as a rule in case of a batch change, which also requires a spinning rotor change, the channel plate adapter is also exchanged.
The above described channel plate adapters have been in actual use for a long time and have proven themselves to be outstanding in connection with almost all fiber materials and almost all yarn thicknesses.
However, it has been shown that in connection with the spinning of yarns made of polyester, or yarns whose material contains a relatively high proportion of polyester, it is necessary to make some concessions in regard to the number of rotor revolutions of the open-end spinning device, because otherwise the danger of melt spots arises. This means that with the known channel adapter plates it is hardly possible without danger to realize rotor revolutions of more than 100,000 revolutions per minute in connection with yarns with a relatively high proportion of polyester.